Tag Archives: health

Improving the accuracy of waist circumference measurement

Waistline needs to be measured for clothes size determination and health evaluation, but the instructions to do it are vague: keep the stomach neutral, neither sucked in nor bulged out, hold the measuring tape not too loosely nor too tight. A person’s waist expands and contracts with the breath, so at which point of the breath cycle should the measurement be taken? How much tension should the measuring tape have?

Averaging several measurements would be more accurate than a single vaguely defined one, both in the sense of replication across different measurers and in the sense of corresponding to the physical quantity of interest (health status, tightness of the clothes). One simple way is to average the measured perimeter of a maximally sucked-in gut and a maximally pushed-out gut.

A better measure, but quite difficult to take, is to average the waist circumference across the whole cycle of breathing in and out, for several cycles. A device to do this would be a loop of flexible measuring tape pulled into a roll by a spring, similarly to a construction measuring tape made of metal. The roll would contain electronics which continuously record how much tape is in the roll, therefore the length of the loop outside the roll. The length data could be averaged to obtain the average waistline.

A more modern method is to use two cameras pointed at the person from two sides at waist height, recording a 3D video of the waist over the breath cycle. The video could then be averaged on a computer to find the mean volume. Whole-body volume could be determined similarly – no need for Archimedes’ Eureka method of submerging the body in a bathtub with a volume scale on it. The volume and the weight determine the density of the body, which gives partial information about its fat percentage.

Reduce temptation by blocking images

Web shops try to tempt customers into unnecessary and even harmful purchases, including grocery and food ordering sites which promote unhealthy meals. The temptation can be reduced by blocking images on shopping websites. I find it useful when ordering food. Similarly, Facebook and news sites try to tempt viewers with clickbait and ads. To reduce my time-wasting, I make the clickbait less attractive by blocking images. The pictures in most news stories do not contribute any information – a story about a firm has a photo of the main building or logo of the firm or the face of its CEO, a “world leaders react to x” story has pictures of said leaders.

The blocking may require a browser extension (“block images”) and each browser and version has a little different steps for this.

In Chromium on 20 Jan 2021, no extension is needed:

1) click the three vertical dots at the top right,

2) click Settings to go to chrome://settings/,

3) scroll down to Site settings, click it,

4) scroll down to Images, click it.

5) Click the Add button to the right of the Block heading. A dialog pops up to enter a web address.

6) Copy the url of the site on which you want to block pictures, for example https://webshop.com into the Site field.

If seeing the images is necessary for some reason, then re-enable images on the website: follow steps 1-4 above, then click the three vertical dots under the Add button under the Block heading. A menu of three options pops up. Click the Allow option.

Alternatively, you may block all images on all websites and then allow only specific sites to show images. For this, follow steps 1-4 above, then click the blue button to the right of the Allow all (recommended) heading. Then click the Add button next to Allow. A dialog pops up to enter a web address. Copy the url of the site on which you want to block pictures, for example https://webshop.com into the Site field.

Virulence of a disease may cause vaccines to be effective

My uninformed speculation: vaccines may be so effective against Covid-19 (90-95% vs flu vaccine 70%) for the same reason why Covid-19 is so infectious – it binds strongly to biochemicals in the organism. If high affinity to the angiotensin-converting enzyme 2 on the surfaces of lung cells is positively correlated with strong binding to antibodies and immune cells, then the immune system, once triggered, removes the viral particles faster for those respiratory viruses that infect cells more easily. Strong binding and the consequent intense immune triggering may also be the reason for the life-threatening immune overreaction (cytokine storm) to the novel coronavirus.
This hypothesis could be tested on a cross-sectional dataset of viral diseases using some measure of the infectiousness of a disease, the effectiveness of a vaccine against it and the frequency of immune overreaction to it.
Infectiousness may be measured by ID50: what number of microbes makes half the organisms exposed to this number sick. This measure depends on the state of the organisms studied. For example, if people’s immune system is weaker in the winter on average, then ID50 measured in the winter is lower than in the summer.
Vaccine effectiveness is typically measured in percent – what fraction of vaccinated people are protected, in the sense that they do not catch the disease in circumstances in which unvaccinated people catch it. This measure of may depend on what the exposure to the disease is. For example, if a large enough dose of the microbe makes everyone sick, vaccinated or no, then exposure to this dose shows zero effect of the vaccine. Similarly, if a small enough dose fails to infect anyone, then the vaccine effect seems zero, but at least the lack of infections among the unvaccinated shows that no information about vaccine efficacy can be obtained from this exposure test.
Immune overreaction needs to be confidently ascribable to the disease studied for it to be a relevant measure for testing the theory about the connection between virulence and vaccine efficacy.

Tissue sampling by piggybacking on vaccination or testing campaigns

Obtaining tissue samples from a large population of healthy individuals is useful for many research and testing applications. Establishing the distribution of genes, transcriptomes, cell distributions and morpologies in a normal population allows comparing clinical laboratory findings to reference values obtained from this baseline. The genetic composition of the population can be used to estimate historical migration patterns in paleoanthropology and selective pressures in evolutionary biology.

Gathering tissue samples from many people is expensive and time-consuming, unless it happens as a byproduct of existing programs. Collecting used vaccination needles or coronavirus nasal swabs that have a few cells attached allows anonymous tissue sampling of almost the entire population. A few cells per person are enough for many analyses in modern biology. Bulk collection of needles or swabs has built-in untraceability of biological material to an individual, which should alleviate privacy concerns and reduce the bureaucratic burden of ethics approvals.

Algae tattooed for doping and oxygen administration

The paper by Qiao et al. (2020) in Science Advances shows that unicellular algae injected near a hypoxic tumour photosynthesise oxygen in the body in response to infrared light with wavelength 660nm that penetrates >4mm into tissues. The oxygen saturation of the tumour rises from 6.2% to 30% in 2 hours after the algae receive a 5-minute laser exposure. The oxygen sensitises the tumour to radiation therapy. No side effects were found from the algae in this or previous research. The performance of the algae stayed the same when these were coated with red blood cell membranes to delay their clearance from the body.

Another application of algae that can produce oxygen in the organism is doping in sports. The algae can be tattooed under skin that is exposed to light containing enough of the wavelengths which the algae use and which can penetrate under the skin. For example, long-distance runners outdoors in warm weather have most of their skin exposed to sunlight, thus have a large surface area suitable for algal oxygen production. The additional oxygen from photosynthesis improves athletic performance. The only question is whether the oxygen generation is quantitatively fast enough to make a difference. In elite sports, every little advantage counts, so athletes are probably willing to use algae tattoos.

The algae are not dangerous even in deep blood vessels and tissues. Eventually the organism clears the algae, but the clearance of foreign particles is slower in the skin than in deep tissues, as evidenced by the persistence of ordinary tattoos. So the algae will last for a daylong competition.

Patients with breathing problems, for example with coronavirus-induced lung inflammation, may also benefit from algae tattooed on a large area of skin which is then illuminated with 660nm light. Such oxygen supplementation reduces the need for mechanical ventilation. Again, the question is the amount of oxygen from a whole-body algal tattoo.

Food refused by the most people

Which food would the greatest fraction of the world population refuse to eat? To make the question interesting, focus on widespread food items, not „interesting” local specialties like surstromming, fermented shark, maggot cheese. My guess is that pork and beef would be the most widely refused, by Muslims and Hindus respectively. Meat in general is considered objectionable by more people than vegan dishes. Refusal of plant-based food is mostly due to allergies, so soy and wheat would be the least popular. In light of this, it is interesting that the main components of the British Airways snack box on 17 May 2020 were made of wheat and pork (Jamon Iberico and a spread made of 57% bacon and 18% pork jowl). The box replaced the usual airline meal. According to British Airways, the reason was to reduce food heating on the plane during the Covid-19 pandemic. I am not sure how reducing cooking is supposed to avoid infection, but even supposing that, the pork-based snacks do not seem optimal by any criterion.

Vegan food is generally cheaper, and among animal-source foods, chicken is the cheapest, followed by turkey. So price cannot be the reason for serving pork. Airlines may try to signal wealth or that they care about passengers by offering „premium” foods, e.g. meat, and not the cheapest kind. However, this signal is undermined by the plastic boxes for the meals, the sloppy mixture of foods in the main box and the small quantities. The goal is clearly not to feed people or to keep them healthy. It does not seem reasonable for the airline to expect that it will give passengers a good taste experience.

Exercise is better than working to buy health insurance

Health insurance does not insure health, but wealth. Exercising to prevent disease is often better than working to buy health insurance to cover treating that disease. For example, cancer, stroke and cardiovascular disease predominantly occur in old age, so insurance against these is highly substitutable with exercise.

The American Association for Critical Illness Insurance in 2011 listed the following average annual premiums by age group for a male nonsmoker based on a $40,000 benefit for treatment of cancer, stroke or heart attack. Age 40: $575 to $610; age 45: $745 to $785; age 50: $940 to $980. Similar premiums in 2019 only buy cancer insurance.

At an after-tax hourly wage of $20, paying these premiums requires 30-50 work hours per year, about 0.6-1 hour per week, or 0.6-1% of waking hours. From a baseline of zero sports, one hour per week of exercise increases lifespan by one year, or by about 1/80 of life expectancy. Whether switching an hour per week from work to exercise (and cutting health insurance to compensate for the lost hourly wage) is a good investment in terms of lifespan depends on how much treatment lengthens life and how much health insurance increases the probability or quality of treatment. Data is difficult to find on both the effect of treatment on lifespan and the effect of health insurance on treatment.

The median survival rate to hospital discharge after EMS-treated out-of-hospital cardiac arrest with any first recorded rhythm is 7.9%. So for serious heart conditions, treatment and thus health insurance does not make much difference. Lung cancer treatment is said to prolong survival by about three months, which also seems small. Even if no health insurance implies no treatment, which is not the case because emergency care is still provided, investing worktime to buy health insurance seems to have a low benefit. People with cancer survive with a probability about 2/3 of the survival probability of a comparable population without cancer, so the upper bound on the benefit of treatment is 2/3 times the probability of getting cancer times the remaining life expectancy. This upper bound is loose, because zero treatment does not reduce the 5-year survival probability to zero.

Preventing overeating by advance cooking

A commitment device that prevents overeating is to only buy food that needs cooking (raw meat or fish, dry goods such as rice, flour, beans), and only buy drinks with zero calories. After each meal, measure out the ingredients for the next meal. The ingredients may be put into a pressure cooker, slow cooker, microwave or other gadget with a timer to cook, so the food is ready at the next mealtime, but not before. This procedure leaves no ready-to-eat food to snack on between mealtimes and no option to eat a larger portion than planned. The reason to portion out the next meal right after the previous meal is to do it while not hungry, thereby preventing oneself from increasing the portion size.

Sufficiently fast food delivery breaks the commitment, because it permits ordering a snack that arrives before the next mealtime. Such delivered food is typically processed and unhealthy. Vending machines, convenience stores, takeout restaurants or other sources of ready food in or near the building also weaken the commitment. Quarantine strengthens the commitment, reducing the temptation to go out seeking food.

Eating a balanced diet is more difficult when restricting food to only categories that need significant preparation time. Fruits and most vegetables can be eaten raw and juices give quick calories due to their high glycaemic index. Frozen fruits and vegetables are more difficult to snack on immediately, thus ease commitment without compromising health. Frozen fruit juice concentrate similarly delays gratification for at least a few minutes. Small berries thaw very quickly in water, so are a temptation.

Lifehacks to prevent overeating (from Youtube): eat in front of a mirror, avoid distractions like a computer, TV or smartphone while eating, use small dishes (Japanese style).

Investing time to gain lifetime

Exercising lengthens lifespan, but the return is diminishing in the amount of exercise. From zero physical activity, one extra hour of exercise per week gains about one year of life expectancy (doi:10.1371/journal.pmed.1001335.t003). Thus investing 1/168 of total weekly hours, or about 1% of the waking hours that are not spent on the quickest possible eating or hygiene, adds about 1/80 of lifespan in developed countries. This time investment has a positive return, because the percentage of lifetime spent on sports is less than the percentage gained.

Exercising may be optimal even for someone who intensely dislikes exercise, because one way to think about this investment is as choosing a year of being dead or a year of exercising plus some extra time living and not exercising. If doing sports is weakly preferred to being dead, then the first few hours of exercise per week are a positive-return investment.

One criticism of the above logic is that the lifetime gained is at the end of life, but the time doing sports is spread evenly throughout life. If extra time when old is worth much less than when young, then investing time in one’s youth to gain years of life in retirement may not be optimal. However, the question then becomes why is time less valuable when old. If the reason is lower ability to enjoy life (due to chronic diseases, cognitive decline, decreased libido, etc), then counterarguments are that exercise increases healthspan (quality-adjusted years of life) and the progress of medicine increases the quality of life in old age over time. If technological progress becomes fast enough to lengthen average lifespan by more than one year each year, then life expectancy becomes infinite. Increasing one’s lifespan to survive until that time then has an infinite return.

If life expectancy does not become infinite in the 21st century, then the diminishing return to exercise in terms of lifespan implies that there is a finite optimal amount of exercise per week, unless one’s utility increases in exercise no matter what fraction of time is spent on it. At 10 hours of physical activity per week, one needs to add about 10 more hours to gain one year of life (doi:10.1371/journal.pmed.1001335.t003). Spending 10% more of one’s waking time to gain 1/80 of lifetime is a negative-return investment in pure time terms, but may still be rational for the increase in health and quality of life.

In the research, exercise is defined as moderate- or vigorous-intensity activities: those with an intensity level of at least three metabolic equivalents (METs) according to the Compendium of Physical Activities. In other words, the energy cost of a given activity divided by the resting energy expenditure should be at least three (the approximate intensity of a brisk walk). The relevant weekly hours of moderate- or vigorous-intensity activity and the years of life gained are in the table below.

Physical Activity Level:0 0.1–3.74 3.75–7.4 7.5–14.9 15.0–22.4 22.5+

Years of life gained: 0 1.8 2.5 3.4 4.2 4.5

More efficient use of rooms and equipment during the shutdown

Instead of the labs, gyms and other rooms standing empty during the shutdown, the same isolation of people could be achieved by allocating each building or other resource to one person. Equipment from gyms or labs could be lent out for the duration of the shutdown, of course keeping a database of who borrowed what and making the borrower liable for its safe return. If only one person uses each object or building the whole time, then there is no cross-contamination or infection-spreading.

Excess demand could be rationed by lottery. Only the winner of the lottery for a resource would be allowed to use the resource, with large penalties for sharing. This would improve efficiency slightly, because one person instead of zero would be using each resource.

If the heat, water and electricity were turned off during the shutdown, then it might be more efficient to let the buildings stand empty, instead of having the utilities on and one person in each building or room. However, the lights in MIT buildings are still on at night, just like before the shutdown (and it seemed wasteful back then already).